1. Field of the Invention
The invention relates to a rack, more particularly to a rack of a simple construction which can be assembled by bare hands without the use of a tool and which can be extended or expanded as desired.
2. Description of the Related Art
Generally, racks commonly available in the market are of a design that provides fixed storage spaces for depositing or displaying objects or articles. The rack itself and the storage spaces therein cannot be suitably expanded as necessary. To improve upon such shortcoming, a rack constructed to have adjustable storage spaces, such as that shown in FIG. 1, has been developed. Such a storage rack, however, is structurally complicated and is troublesome to assemble.
Specifically, the rack of adjustable storage spaces in the prior art, shown in perspective view in FIG. 1, essentially comprises two side frames 1, a plurality of cross bars 2, a plurality of first clamp pieces 21 and a plurality of support panels 3. Each of the side frames 1 consists of a pair of juxtaposed subframes 11 of generally inverted "U" shape each having a pair of legs. Each pair of subframes 11 are integrally connected by a plurality of brace members 12 placed between two adjacent legs of the subframes 11 and welded thereto. The side frames 1 each have two bottom ends provided with two casters 14, respectively. Each of the cross bars 2 has two second clamp pieces 22 complementary to the first clamp pieces 21 provided at the two ends thereof. As best shown in FIG. 2, each second clamp piece 22 has two recesses 23 adapted to embrace partially two adjacent legs of the subframes 11, respectively, and a threaded hole 24 between the two recesses 23. Each of the first clamp pieces 21 is likewise provided with two recesses 25 and a threaded hole 26 thereon which correspond to the recesses 23 and threaded hole 24 of the second clamp pieces 22, respectively.
To assemble into a rack, the plurality of cross bars 2 are firstly mounted to each of the side frames 1 in a position bridging the two opposing pairs of legs of the two subframes 11 and at predetermined heights along the length of the legs of the subframes 11, the cross bars 2 in one of the side frames 1 being horizontally aligned with the cross bars 2 in the other one of the side frames 1. To attach a cross bar 2 to the legs of the subframes 11, the cross bar 2 is positioned such that two adjacent legs of the two subframes 11 are partially received in and abut against the two recesses 23, respectively, of the second clamp piece 22 at one end of the cross bar 2 while the other two adjacent legs are partially received in and abut against the two recesses 23, respectively, of the second clamp piece 22 at the other end of the cross bar 2. The first clamp pieces 21 are subsequently sleeved onto the outer side of the subframes 11 to mate with the second clamp pieces 22 on the cross bars 2, with the threaded hole 24 on each second clamp piece 22 aligned with the threaded hole 26 on each first clamp piece 21 and a threaded bolt 27 inserted therein. Thus, the cross bars 2 are mounted at predetermined heights on the side frames 1 through the clamping engagement of the clamp pieces 21,22. The support panels 3, which are rectangular in shape, are then placed and supported on the pairs of horizontally aligned cross bars 2, respectively, by a hook member 31 protruding from each of the four comers of the support panels 6 thereof and engaging the cross bars 2. To increase the stability of the assembled rack, two reinforcing rods 13 are further provided between the two side frames 1 in intersecting arrangement.
In use, the number of support panels 3 on the rack may be suitably increased or decreased to adjust the size and number of the storage spaces as required. The rack may be expanded sidewise by connecting another side frame to the two assembled side frame on either side thereof and mounting a suitable number of cross bars 2 and support panels 3 thereon, thereby increasing the capacity of the rack. While such a rack can achieve the intended effects, it is found that it still has the following shortcomings:
(1) Tools are necessary during assembly: To assemble the rack, the cross bars 2 are secured to the legs of the subframes 11 of the side frames 1 through the second clamp piece 22 provided at each of the two ends of the cross bars 2 in cooperation with the corresponding first clamp piece 21 together which clamps the legs of the subframes 11, the first and second clamp pieces 21,22 being secured together by the threaded connection of the threaded bolt or screw 27. In view of this, a tool is necessary to screw the threaded bolt 27 during assembly to be able to securely clamp the first and second clamp pieces 21,22 onto the side frames 1.
(2) The assembly operation is troublesome: During assembly of the rack, the second clamp pieces 22 on each cross bar 2 cooperate with corresponding first clamp pieces 21 to clamp the cross bars 2 to the side frames 1. The cross bars 2 are thus secured one by one to the side frame 1 using a tool. FIG. 1 shows five pairs of cross bars mounted on the two side frames 1. With a greater number of cross bars to be mounted one by one on the side frames 1, the assembly of the rack would be quite time-consuming and tedious.
(3) The reinforcing structure for increasing stability of the storage rack is troublesome and is a waste of material: For mounting various support panels 3, the rack is designed to have cross bars 2 spanning the opposing legs of the subframes 11, and corresponding hook members 31 provided at the four comers of the support panels 3. However, such a connection is not sufficiently secure. To increase the stability of the assembled rack, two reinforcing rods 13 are further provided between the two side frames 1. Such a design is not only more troublesome but also adds to the material cost.
Therefore, there is still room for improvement upon such a rack having adjustable storage spaces. The present invention is contrived with a view to alleviate the above disadvantages of the prior art rack in terms of assembly.